The subject matter of this United States patent application is related to a second United States patent application entitled "Piezoelectric Motor" by T. Shibuya, Ser. No. 770,669, filed currently herewith.
The invention relates to an energy converting device employing the transverse effect of a piezoelectric element. More particularly, the invention relates to an actuator controlled by an electric signal which converts electric energy to linear motion.
Conventionally, stepping motors, electric magnets, and solenoids have been used as a general type of actuator. However, these devices generally cause response time lags due to their electric inductances. For example, in the case of a stepping motor, it cannot stop at a predetermined position accurately due to its inertia. Thus, controlling the stepping motor is complicated. In the case of an electric magnet or a solenoid, due to their lower energy conversion efficiency, power consumption is fairly high. This results in an overheated, shorter life. To overcome these faults, such equipment required larger and heavier construction.
For instance, in the case of a printer using an electric magnet, a movement is attracted by energizing the electric magnet, and electric wires strike an ink ribbon or recording paper against a platen for printing. When deenergized, the movement resumes to its original position by spring action.
Such types of printers cause a fairly heavy movement to go and return in a circular-arc line and their printing speed is thus limited. Besides, such printing causes shock and a noisy metallic sound when the movement strikes. Consequently, such printers sometimes require devices to absorb the sounds and shocks and thus the number of parts for such devices are increased.
It is therefore an object of the invention to eliminate the above described problems associated with known actuators, and to provide a light-weight, noiseless, componentless and firmly constructed actuator.